Phosphate-starved plants reduce phosphatidylcholine content presumably to provide an internal phosphate source while replacing membrane phospholipids by galactolipids, a process termed membrane lipid remodeling. However, whether the metabolic fate of released phosphocholine is a phosphate source remains elusive because primary phosphocholine phosphatases in vivo are unknown in seed plants. Here, we show that PECP1 and PS2 are the primary phosphocholine phosphatases in Arabidopsis and function redundantly under phosphate starvation. Under phosphate starvation, the double knockout mutant of PECP1 and PS2 showed reduced content of choline but no severe growth phenotype, which suggests that phosphocholine dephosphorylation is not likely a major source of internal phosphate reserve. We identified primary phosphocholine phosphatases, demonstrated their involvement under phosphate starvation, and updated the metabolic map of membrane lipid remodeling. (C) 2017 Elsevier Inc. All rights reserved.